Potentiality of the Raw Material Coal Base from the Gacko Deposit in a Function of Providing the Energy Fuel for Strategic Planning of the Tpp Gacko 2

MINING AND METALLURGY INSTITUTE BOR ISSN: 2334-8836 (Štampano izdanje) UDK: 622 ISSN: 2406-1395 (Online)

UDK: 622.333/.271(045)=111 doi:10.5937/mmeb1904011V

Boško Vuković*, Aleksej Milošević**

POTENTIALITY OF THE RAW MATERIAL COAL BASE FROM THE GACKO DEPOSIT IN A FUNCTION OF PROVIDING THE ENERGY FUEL FOR STRATEGIC PLANNING OF THE TPP GACKO 2

Abstract

Coal resources, in addition to oil, gas and uranium as a non-renewable and hydropotential as a renewable energy source, represent the most significant part of energy potential and an energy source of strategic importance on the Republic of Srpska. The modern pace of technological and industrial development causes a permanent increase in coal exploitation and consumption. The use of this resource must be planned and extremely rational. Coal deposits in the Republc Srpska are differed in the structure and quantities of reserves, geological and technical-economic conditions of exploitation and quality. Geological reserves of the Gacko coal deposit amount to 330 Mt. According to the current geological documentation, the balance reserves are ≈182 Mt, with an energy potential of 545 TWh. According to the processed performance indicators, the balance and mineable reserves of coal enable a long-term supply of fuel for the current and future thermal power plant under the favorable economic conditions. In order to provide the required amount of energy for operation the existing and "new" thermal power plant in Gacko, it is necessary to carry out the geological explorations in order to reproduce the mineral and raw material base. The duty of every company engaged in exploitation the coal energy resources is a continuous performance of geological explorations in order to find the new ones or transfer the existing reserves into a higher category. The future development and level of coal production from the Gacko deposit will mostly depend on the electricity production in the Gacko Thermal Power Plant. It would certainly strive for fulfillment the basic conditions, i.e. the cost of coal heat utilization, as in many other countries, be at least approximately competitive with the cost of heat from the other primary energy sources (hydro sources, imported energy, etc.).In order that the Gacko non-renewable energy resource would survive and evolve in a particular environment, it must have a clearly defined purpose of existence. This purpose of existence is primarily reduced to a multiphase process of providing and using a non-renewable energy resource in accordance with the realistic natural, economic and ecological opportunities, in relation to which there are the expressed needs in a wider or narrower environment. Keywords: coal, Gacko deposit, open pit, energy fuel, thermal power plant

1 INTRODUCTION

The Gacko field and carbonaceous fields are covered by the Quaternary sedi- Neogene sediments deposited in its former ments below which are the Neogene for- 2 depression are located in the far southeast mations, covering an area of about 40 km . of the Republic of Srpska on the border The Neogene sediments are distributed over with Montenegro. Three quarters of the an area of about 16.5 km long, from

*Mine and TPP Gacko, Industrial zone bb, e-mail: [email protected] **Faculty of Mining Prijedor, University in Banja Luka, e-mail: [email protected]

No. 3-4, 2019 11 Mining & Metallurgy Engineering Bor Nadanić in the northwest, to Gareva and coal seams, only for the main seam is Dobrelja in the southeast, with the maxi- 9.36 t/m2. For all three coal levels of the mum width of about 3 km [2]. first coal seam, the average coal content is The Gacko deposit contains lig- 13.73 t/m2. The second coal seam is cha- nite/brown-lignite coal type as an economic racterized by the uniform development raw material type. It is used almost exclu- throughout the deposit with average coal sively as a thermal energy fuel, for the needs content of 13.46 t/m2. The average coal of the Thermal Power Plant in Gacko and is bearing content in the contours of balance one of the strategic raw materials of the Re- reserves of the roof seams of coal zone is public of Srpska. Coal from the Gacko de- 7.12 t/m2. posit is a non-renewable energy mineral raw There are 36.1 Mt of coal in the Gacko material of the primary economic im- coal deposit, category C2 mainly in the portance for the Republic of Srpska. deepest parts of the Eastern Field. This The coal mines in the Republic of practically means that there is a real po- Srpska, during their production activities, tential for finding the new coal reserves in encounter the specific problems, issues and this area. If the new reserves would be challenges [10]. The same are related both found (for which there are favorable mi- to the quantity and quality of mineral raw neral genetic preconditions), the open pit materials, as well as to the organizational life would be increased, so the coal mine and production activity. They also share a in Gacko would be a long-term economic need to improve and modernize the produc- facility with a significant impact on de- tion and work organization technology. The velopment the other economies and social latter is particularly pronounced in the case activities in the Municipality of Gacko. of the Gacko coal deposit, that is, the mine Within this, it is estimated that construc- supplying the Gacko Thermal Power Plant tion of the second and, in perspective the with the raw material. third phase of the Thermal Power Plant, has its full justification. 2 COAL RESOURCES FROM GACKO - ENERGY FUEL FOR To evaluate the possibility of energy de- THE CURRENT AND FUTURE velopment on the basis of coal use from the THERMAL POWER PLANTS deposit "Gacko", it is necessary to know the actual coal reserves, mining-geological con- Geological reserves of the Gacko coal ditions, hydrogeological conditions, geome- deposit amount to 330 Mt [8]. According chanical parameters of waste sediments to the current geological documentation, (overburden), quality and usability of coal, the balance reserves are ≈182 Mt, with an possibility of development the cheaper sur- energy potential of 545 TWh. Due to the face exploitation, possibility of applications total quantity of ore reserves and quality, the modern mechanization at the open pit, the Gacko coal deposit is the most im- i.e. mechanized high-performance comple- portant source of this raw material for the xes in surface exploitation. In principle, over needs of thermal power plants in the Re- a longer period of exploitation, it is realistic public of Srpska. to expect a more pronounced impact of vari- The average coal bearing content in ous risks, within which the geological, mi- the Gacko coal deposit, by the individual ning and economic risks are dominated.

No. 3-4, 2019 12 Mining & Metallurgy Engineering Bor

3 TECHNOLOGICAL PROPERTIES OF THE RAW MATERIAL BASE OF COAL

Technological properties of the raw The basic aspects of utilization the exis- material base of coal are determined by its ting coal reserves, in order to obtain the mineral and chemical composition, struc- quality fuel for the thermal power plant, tural-textural characteristics, granulome- require a professional and modern approach tric characteristics, amount of useful and in order to obtain the adequate, maximally harmful or undesirable components, as rational technological effects in the proce- well as the characteristics of their location sses of coal production and combustion. in the deposit. For evaluation the coal Considering that coal is a heterogeneous quality from the Gacko deposit, its ther- raw material, that its composition and pro- mal value is of the greatest importance. perties can differ from the same seam, there The use of raw lignite in a batch form in is a need to obtain as uniform and high- a wider and general consumption and indus- quality characteristics as possible by the try is justified only within the economic technological solutions and processes. For transport radius because its thermal value is these reasons, all issues related to ensuring low. This means that the sale of pre-sorted the guaranteed quality of coal as a fuel for raw lignite as fuel in smaller urban settle- the thermal power plant are directed to fin- ments (closer to the mine) would have the ding the technological solutions in order to positive economic effects. However, most improve and harmonize the quality of of the raw lignite produced from the Gacko mined coal. Solving the problem of provi- deposit, as well as in the Republic of ding coal of uniform quality and composi- Srpska, is used in the thermal power plants tion can be realized through the technologi- for electricity generation [7]. cal process of refining (cleaning) the run-of- The qualitative characteristics of coal as mine coal [5]. an energy fuel from the Gacko deposit have Previous solving the above problem in been defined by the classical immediate the mine has been in a direction of selection analyzes. The results of such research often the optimum coal mining technology, deviate from those tested in practice. The which implied the application of selective coal quality studies were carried out in a exploitation. Coal in the deposit of the manner that is not adapted to the require- Gacko basin is of complex geological ments of selective exploitation. However, structure, layered with a large number of no low thermal value interlayers, such as barren interlayers of low power and, there- clay coal or coal clays, were precisely de- fore, very ungrateful for exploitation and fined, which also reduce the thermal value preparation. Selective coal mining partially of coal. All of this had a direct effect on solves the problem, but due to the above poor separation of the waste interlayers characteristics of coal series, it encounters from coal and decrease of its thermal value. difficulties and does not produce the good Coal intended as a thermal energy fuel and enough results. It is obvious that the present coal intended for the general consumption exploitation results in a kind of dilution, i.e. are delivered to the final consumers with- a decrease in the quality of raw material, out additional technological processes for which is reflected in the lower thermal va- coal refining and classification. lue of coal that is burned in comparison

No. 3-4, 2019 13 Mining & Metallurgy Engineering Bor with the heat value, which, according to the conditions of limited greenhouse gas research, was calculated for "clean" coal. emissions; As this problem has not been satisfactorily - Aligning the legislation with the legal resolved previously, it should be consi- heritage of the European Union. dered as an important technical and exploi- An ambitious plan of development ac- tation factor and in future exploitation in tivities needs to be enacted and imple- the new Open Pit Gacko. mented to achieve these framework- defined objectives in the coal capacities of 4 THE OBJECTIVES OF THE the Republic of Srpska. According to this DEVELOPMENT STRATEGY OF plan, it is estimated that the planned vo- ENERGY SECTOR OF THE RS lume of capital should be invested in a The general objective of the develop- new and revitalization the existing equipment strategy of thermal power sector is ment and other projects in the coal mines defined in the Energy Strategy of the Re- in the Republic of Srpska. public of Srpska until 2030. The strategic The total energy demand in the Repub- document defines the general objectives, lic of Srpska is met by the consumption of which are the basis for strategic planning coal, liquid fuels, gaseous fuels, hydropo- the development of the Gacko thermal wer and firewood. Coal accounts for the power complex. The national strategic ob- largest share of total energy consumption - jectives are as follows [9]: about 40%. Coal is predominantly used for - Providing the required amount of the electricity production in the thermal energy, primarily coal, for the thermal power plants (over 90%) while the rest is power plants in order to ensure regu- used for the other commercial purposes. lar and secure electricity supply to the When considering the energy reserves economy and citizens in the area of and potential of the Republic of Srpska, coal represents the dominant energy feed- the Republic of Srpska. The provision stock with the total balance reserves of of required energy amount should be 684 Mt, 390 Mt of lignite and 294 Mt of done at economically sustainable brown coal. This energy resource will prices, taking into account the prob- continue to be based on the energy deve- lems of energy poverty; lopment of the Republic of Srpska, given - Increasing the efficiency of produc- that it is planned to increase the coal pro- tion the non-renewable energy re- duction up to 9.3 x 106 tons of coal by sources; 2025, with an estimate of investment in - Creation the conditions for gradual the coal production area in 2010-2030 of 6 opening the electricity market and in- 655 x 10 KM. vestment in the thermal energy sector; - Establishment an efficient system for 5 LONG-TERM COAL MINING promoting the thermal energy effi- STRATEGY FROM THE GACKO DEPOSIT ciency and use the non-renewable energy sources in accordance with the Development strategy of the Gacko set goals and obligations that will re- Thermal Power Complex, based on the sult from the membership of Bosnia basic document, has the main objective of and Herzegovina in the EU; countering the Gacko coal reserves, whose - Providing a sustainable development exploitation at economically favorable va- of the thermal power sector under lues can provide the energy fuel for both the

No. 3-4, 2019 14 Mining & Metallurgy Engineering Bor existing and future Thermal Power Plant - The east boundary is defined by the Gacko 2. On the basis of this, the main ob- existing work front; jectives have been defined for development - The west border is represented by a the strategic document "Strategy of Mining geological-exploration profile 55-55'. and Technological Opening, Development, Optimization and Maintenance of the Coal After determining the essential parame- Production Continuity with Preparation the ters of the open pit exploitation, based on Feasibility Study for Introduction a Dry the adopted criteria, ranking of the consi- Gravity Separation Process". Prior to draf- dered alternatives was carried out and thus ting of this document, the objectives have formed the basis for making decisions on been set that would be solved by the strate- the future development of both the mining gy, and the same primarily address the fol- and thermal power part of the Mine and lowing [4]: TPP Gacko. The expected results of the - Defining the basic directions of de- Strategy are also the formation of techno- velopment the open pit coal exploita- logical solutions for coal exploitation and tion for the purpose of continuous, processing, which will represent a frame- stable and reliable supply of the work for opening and development the fu- Thermal Power Plant Gacko with coal ture Gacko open pit and the basis for mi- of appropriate quality; ning design. - Defining the optimal technological The future development and level of parameters of the system of open pit coal production from the Gacko deposit exploitation on the basis of the re- will depend mostly on the production of sults of conducted analysis and op- electricity in the active Gacko 1 Thermal timization based on the economic Power Plant and the future Gacko 2. In this criteria; case, the basic condition should be fulfilled, i.e. the cost of coal heat utilization, as in - Optimal utilization the existing coal many other countries, be at least approxi- resources in the area defined by the mately competitive with the cost of heat Program task; from the other primary energy sources (hy- - Determining the possibilities and dro sources, imported energy, etc.). Since conditions of application the new the mine and thermal power plant are the technologies of coal exploitation and unique enterprises, the revitalization of the processing in order to optimize the existing thermal power plant and develop- techno-economic parameters, i.e. to ment of the mine are interco-nnected. De- maximize the financial effects of velopment of the mine will be enabled by production with improvement quality the sale of electricity in the surrounding of produced coal. markets (formation of a free electricity The domain of solution for develop- market in the region, shutdown of indivi- ment the open pit exploitation in the dual power plants in the region, demand for Gacko coal basin is formulated within the electricity) and improvement the coal pro- following limitations: cessing technology with a possibility of use - The south and north boundaries of the the lower coal quality. On the other hand, studied area is defined by the limits of entering the market also means exposure to open pits and landfills, according to the price and demand volatility (uncertainty the Regulation Plan of the Mine and and instability of income). In addition, the Thermal Power Plant Gacko (2011); future development will also depend on

No. 3-4, 2019 15 Mining & Metallurgy Engineering Bor tightening the environmental require- lar supply of coal to the Gacko Thermal ments [7]. Power Plant was ensured. In order to supply coal regularly to the Gacko Thermal Power Plant, a new con- 5.1 Optimum variant of coal exploitation ceptual solution for the open pit coal ex- from the Gacko deposit ploitation from the Gacko deposit has been adopted since 2015. Excavation of the A long-term strategy of coal exploitation overburden, coal and seam waste in the area is elaborated in the "Strategy of Mining and of Field "C", due to a lack of adequate ex- Technological Opening, Development, Opti- cavation and transport equipment, has been mization and Maintenance of the Coal Pro- made difficult with constant delays in the duction with Introduction the Enrichment implementation of plans for the open pit Process of Coal of Dry Separation at the excavation. This resulted in a stable supply Open Pit Gacko", done by the Mining and of coal to the Thermal Power Plant from Metallurgy Institute Bor, Republic of Serbia. the active open pit (Field “C”). The con- The following text briefly outlines the ducted optimization of possible variants of mining-geological and economic indicators development the open pit have highlighted of Variant 3, which is elaborated in detail two perspective zones with a possibility of efficient and economically favorable coal in the Strategy [4]. exploitation, as well as [3]: The open pit boundaries in the in a part of the deposit Field C and East Field, with- - locality of the Field "C" (Central out limitation by the geological exploration Field), where the main and first sub- profile 55-55'. Optimization of the Open Pit coal seams are exploited, and contour in a plan and by depth was made - roof coal area where the third and se- using the Whittle Fx software. cond roof coal seams are exploited. Figure 1 shows a contour of the open By opening the open pit at the site of pit from Whittle, designed after processing the roof coal zone, continuity in the regu in the basic software Gemcom.

Figure 1 View of the Open Pit 24 designed in the basic Gemcom software on the basis of contours from Whittle (Source: Z.Vaduveskovic, S. Stepanovic et al., 2015)

No. 3-4, 2019 16 Mining & Metallurgy Engineering Bor Table 1 shows the calculation of coal overburden and associated interlayer amount in the roof and floor seams and waste.

Table 1 Amounts of coal, overburden and interlayer waste in a contour of the Open Pit – Variant 3 Volume Volume mass Amount DTE Mineral raw material m3 t/ m3 tx1000 kJ/kg Roof seam coal 48,246.930 1.300 62,721.006 7,393.35 Main and floor seam coal 32,231.947 1.263 40,722.290 9,531.19 ∑ COAL 80,478.876 1.285 103,443.296 8,234.95 ∑ WASTE 1 342,040.475 1.740 594,994.468 ∑ EXCAVATION 422,519.352 1.653 698,437.763 3 Ko=3.04 m /t; 5.75 t/t (Source: Z. Vaduvesković, S. Stepanović et al., 2015)

Based on the needs of the thermal power required quality. Based on the conducted plant for an adequate amount of energy, the research, the X-Ray sensor method of coal service life is 36.5 years. Considering the separation/refining was adopted for further qualitative and structural characteristics of elaboration. coal from the Central Field deposit, using of An overview of the work dynamics only selective exploitation cannot ensure the over five-year periods is given in Ta- stable production of coal of the minimum ble 2.

Table 2 Dynamics of the work development in Variant 3

Exploitation period 1-5 6-10 11-15 16-20 21-25 26-30 30-36 (years) Run-of-mine coal (x1000 t) 13,12 14,049 14,25 14,87 15,612 15,519 18,561 Run-of-mine coal on a 6,100 3,973 4,206 4,863 5,607 5,519 6,561 landfill (x1000 t) DTE - run-of-mine coal on 7,664 8,188 8,337 8,043 8,317 8,380 7,844 a landfill (kJ/kg) Refined coal on a landfill 4,606 6,610 6,588 6,566 6,563 6,560 7,872 (x1000 t) DTE - refined coal on a 9,318 9,626 9,865 9,088 8,201 8,433 8,657 landfill (kJ/kg) DTE - coal on a landfill 8,375 9,086 9,270 8,643 8,255 8,409 51,942 (kJ/kg) Total energy on a landfill (TJ) 89,675 96,155 100,01 98,789 100,458 101,568 119,609 Total waste (x1000 t) 81,277 81,397 95,972 96,833 82,543 88,342 68,630 (Source: Z. Vaduvesković, S. Stepanović et al., 2015)

The basic economic indicators of presented in Table 3. exploitation for the adopted variant are

No. 3-4, 2019 17 Mining & Metallurgy Engineering Bor Table 3 Economic indicators of Variant 3

Calculation of economic indicators, was Profitability indicator Variant 3 made taking into account, in addition to the capital and operating costs of the Internal rate of return (%) 16.66 mining section, also the investments in in refining plant, standardized costs of the Net present value (KM) 467,010,627 refining process and benefits generated in the thermal power plant. Return period (years) 7 (Source: Z. Vaduvesković, S. Stepanović et al., 2015)

Based on the performance indicators, the number of working-age population of coefficient of waste and contoured coal re- Gacko and neighboring municipalities and serves, the Variant 3 was selected as the foreign exchange inflow through the sale of most economically advantageous because it electricity to the foreign market. The inter- shall ensure regular supply of coal to the national competitiveness of the national Thermal Power Plant Gacko 1 and future energy sector of the Republic of Srpska is Thermal Power Plant Gacko 2. characterized by the ability of energy companies for successful engagement in the 6 NATIONAL COST-EFFECTIVENESS international economic relations. The Gacko OF COAL USAGE FROM THE energy complex achieves the same through GACKO DEPOSIT the production of goods (coal and electrici- In the previous coal and electricity pro- ty) that can meet the international market duction from the power complex Gacko, a standards, but at the same time retain and commercial viability was achieved, which is increase a long-term real household income. a direct financial benefit to the energy sector Due to a high demand for commercial coal, of the Republic of Srpska. However, the as well as a high electricity demand of the commercial viability, which is practically countries in the region, it is expected that determined by the market economy and its the coal prices will increase in accordance principles, cannot give a clear picture of with the market principles, in comparison contribution the coal and electricity produc- with the current state of free pricing at the tion to the national economy of the Republic company level. of Srpska. Sustainable use of the coal energy resource In order to measure the contribution of in Gacko offers a solution for achievement coal production to the national economy, it the basic objectives related to the security of is necessary to consider the national cost- supply the present and future thermal power effectiveness, considering the direct and plant, as well as rationalization in its exploi- indirect effects of interest to the Republic of tation. This would provide the conditions to the future generations to use the coal re- Srpska and its long-term and stable deve- sources within the timeframe and reserves lopment. National profitability from the available to Gacko. The main objective in Gacko Energy Complex is achieved through the mineral strategy of this resource is to the positive effects on employment, foreign provide the all necessary preconditions for exchange inflows and international compe- rational and efficient management and sus- titiveness. The effects on employment were tainable use of available energy potential in achieved through employment of a large relation to the established reserves, envi-

No. 3-4, 2019 18 Mining & Metallurgy Engineering Bor ronmental impact and socio-economic de- resource is to provide the necessary precon- velopment. ditions for rational and efficient management and sustainable use the available ener- CONCLUDING CONSIDERATIONS gy potential with respect to the established reserves, environmental impact and socio- The role of thermal power sector that economic development [7]. uses coal as a non-renewable energy source is to support the development and growth of REFERENCES the economy of the Republic of Srpska considering the environmental protection. The [1] Milovanović D. (1991): Some Current development of thermal power sector will Issues of Economic Evaluation the result in technological development, Mineral Deposits in Market Condi- strengthening of domestic companies, in- tions, Tehnika, Rudarstvo, geologija i crease of investments and increase of com- metalurgija, No. 3-4, Belgrade (in Serbian) petitiveness of the economy of the Republic of Srpska in relation to the coun-tries in the [2] Nikolić D. at all. (2013): Elaborate on Coal Reserves in the Gacko Deposit region. The Gacko mine and Thermal Po- with Condition as of 30/06/2012, wer Plant have a significant position in the GEOING-group, Belgrade (in Serbian) energy sector of the Republic of Srpska. In [3] Vaduvesković Z. (2014): Presentation the strategic document, the countered coal of the Conceptual Design for reserves of the Gacko Coal Basin enable a Development the Coal Mine Gacko, regular supply of coal to the TPP Gacko 1 MMI Bor, R. Serbia (in Serbian) TPP Gacko 2, and the remain-ning reserves [4] Vaduvesković Z., S. Stepanović: not treated by the selected Variant 3, repre- (2015): Strategy of the Mining- sent the basis for further mining-geological Technological Opening, Development, and economic analyzes and represent the Optimization and Maintenance a base for construction another one thermal Continuity in Coal Production with power plant (potential Gacko 3). Introduction a Refining Coal Method The design solution, combined with of Dry Separation at the Open Pit – the coal exploitation from the Field "C" MMI Bor, R. Serbia (in Serbian) and roof coal zone, provides an econo- [5] Vuković B., Petrović M., Petrović P., mically optimal coefficient of overburden Bijelić V., Stanimirović B. (2004): and continuity of coal exploitation from Possibility of Improvement the Quality the Gacko deposit. of Coal from the Open Pit "Gračanica" Gacko by Introduction the Paranaby The planned use of the coal energy re- Technology, Scientific and source in Gacko offers a solution for Professional Conference "Contem- achievement the basic objectives related to porary Achievements in the the secure supply of the present and future Exploration, Exploitation and Use of thermal power plant, as well as rationaliza- the Mineral Resources in the Republic tion in its exploitation. This would provide of Srpska", Gacko (in Serbian) to the future generations the conditions to [6] Vuković B. (2000): Complex use the coal resources within the timeframe Assessment of the Gacko Coal basin and reserves available in Gacko. The main and its Importance for the Overall objective in the mineral strategy of this Energy Potential of the Republic of Srpska, Master Thesis, Faculty of

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